Collective bargaining history

While the existence of bargaining history is a factor that may be reckoned with in determining the appropriate bargaining unit, the same is not decisive or conclusive. Other factors must be considered. The test of grouping is community or mutuality of interests. This is so because "the basic test of an asserted bargaining unit's acceptability is whether or not it is fundamentally the combination which will best assure to all employees the exercise of their collective bargaining rights." (103 Phil. 1103, cited in G.R. No. 79526, December 21, 1990)